I will be spending 5 months in South America and hitting a bunch of treks in Patagonia and Peru. My treks in Patagonia will be January and February and ranging from 2 to 8 nights in length, Torres del Paine Circuit, Fitz Roy, pretty much anything popular in Argentina. Treks in Peru are in May, Salkantay trek to Machu Picchu, Santa Cruz circuit, maybe some others. I'm going to be bringing an 18 oz Osprey Hornet 24 for keeping valuables safe on buses, day trips in cities, day hikes, and storing extra clothing at hostels while I go out on treks with my main pack.

This is my gear list for treks (minus normal clothes for use in cities that will be stored in my osprey hornet, etc). I've never done any overnight backpacking and this is solo. I've put things in parentheses if I'm unsure and need advice

ULA CatalystTrash compactor bag linerZpacks cuban fiber roll top for down bag and certain clothing piecesEverything else will either be free in my bag or in ziplocs

Sleeping:Scarp 1 with 2 extra guys and stakes for sleeve pulloutsTyvek ground sheetREI sub kilo 20F down bagThermarest Xtherm regular ( do people fold these flat against their bag or roll it up in the sack that it came with that also is used to inflate it or inflate with mouth?)Cocoon hyperlite pillow

Extras:First aid kit - haven't put together yetRepair kit - thread and needle, duct tape, kid that came with sleeping padLighter and box of matchesMapsKatadyn purifying tabletsLeatherman Juice S2Black diamond headlamp and spare batteriesDocuments in ziploc - passport, etctimex watch - just for time and alarmBlack diamond distance z-poleWhistleJust going to use plastic bottles instead of nalgene, no bladder(Have a compass but my Patagonia book says it needs to be a global one to work in southern hemisphere - I don't even know how to use a compass anyway)

I did a similar trip in Peru and Bolivia, and probably would have been cold with that upper body, though I was there in July, when it's a bit colder. I took a mb thermawrap and rab infinity. We also ended up doing the Huayhuash instead of Santa Cruz, and Choquequirao instead of Salkantay. They're worth a look.

There was a series of articles here about backpacking in South America, here's one:http://www.backpackinglight.com/cgi-bin/backpackinglight/global_test_gear_list_part_2.html?id=jreYwd6D:69.89.31.227

I'm pretty sure it's quite a bit colder in July. I've heard that for example in TDP in January it won't hit freezing. I might take a 100wt fleece as well. I'm I'll be okay with a Cap 2, fleece, houdini, MB parka, rain shell, and hat if I get cold.